Collet



July 2, 1945. M R 2,403,136

COLLET Filed Aug. 17, 1944 INVENYI'OR' 71607 Mamie/r .1702? ATTO R N EYPatented July 2, 1946 UNITED. STATES PATENT OFFICE Arthur MerrickStoner, West Hartford, Conn, assignor to The Jacobs ManufacturingCompany,

Hartford, Conn., a corporation of Connecticut Application August 17,1944', Serial No. 549,847

This invention relates to a collet of novel structure which is of simpleinexpensive construction and has many advantages over such' devices ashave been available heretofore.

The object of this invention is to improve upon the devices shown in myPatent No. 2,346,706, issued April 18, 1944, and on those shown in myco-pending application, Serial No. 521,097, filed February 4, 1944.

More specifically, its object is to provide a collet of the type shownin the aforesaid patent and application in which the rigid grippingmembers are inserted in a resilient retainer molded to receive them,with attendant advantages which will appear in the followingspecification.

Referring to the drawing:

Fig. 1 is a sectional side elevation of a collet which is made accordingto and embodies my invention.

Figs. 2 and 3 are transverse sectional elevations of the structure shownin Fig. l,- the sections being taken respectively on the lines 2-2 and33 of the latter figure. s

Fig. 4 is a side elevation of a body of resilient material which forms apart of the collet illustrated in the preceding figures.

Fig. 5 is a front elevation of the body shown in Fig. 4 with a partbroken away and shown in a section taken on the line 55 of Fig. 4.

Figs. 6, 7 and 8 are sectional elevations of a part of resilient bodiesof modified forms. The position of one of the gripping members isrepresented in these figures in dotted lines.

Fig. 9 is a central sectional side elevation of a chuck of which acollet of the novel construction disclosed herein is a part. This figureis included to show a way in which the collet may be used.

The collet comprises a plurality of gripping members 10 of rigidmaterial, such as hardened steel. These are angularly disposed about acommon axis A-A with their inner edges 1 I equidistant from and paralleltherewith. Their forward ends may be chamfered as at I2. A notch I3 iscut in the inner edge of each of the gripping members intermediate itsends. I4, l5 designate spaced perforations through the gripping members.The major portion of the outer edges I6 are beveled and lie in afrustroconical surface. The rear end of the gripping members isdesignated by the numeral H.

20 is a retainer in the form of a hollow externally tapered body ofresilient material, such as oil resistant synthetic rubber. This ismolded with radially disposed longitudinal slots 2| for receiving andpositioning the gripping members.

4 Claims. (01. 279-44) The slots extend through the body. except forportions 22 across the bottoms of the slots; The longitudinal width ofthe portions 22 corresponds to that of the notches l3 and they havepreferably a cross-sectional form to fit these notches. The inner andouter surfaces of these portions are substantially circular but betweenthem longitudinal. grooves 23 are formed in theinner surface of theretainer to facilitate the folding operation of the'parts of the bodybetween adjacent gripping members which is particularly described in theaforesaid application Serial'No. 521,097.

Bosses 2E and 25 project inwardly in mutual alinement from oppositesides of'the slots 2|. The rear end of the body is designated by '26 andits front end by 21.. a

In assembling the collet the body is bent to spread the bosses 24, 25apart sulficiently to permit the gripping members III to pass them. Thegripping members are inserted with their notches straddling the portions22 of the body. Then when their inner edges II are moved intoparallelism with the axis A-A, the perforations I4 and [5. are inalinement with the bosses 24, 25 and when the body is allowed to resumeits normal position the bosses enter the perforations from oppositesides of the gripping members and hold the latter in desired positions.

The chuck shown in Fig. 9 comprises a hollow body 30, the rear portionof which is threadedat 3| for attachment to a machine tool. Theforwardportion of the body is internally threaded, as at 32. A transverseabutment 33 is formed back of this internally threaded portion.

The rear ends I! of the grip ing members of the collet are seated on theabutment surface 33. 34 is a pressure member externally threaded to fitthe threads 32. This memberhas a conical cam surface 35 having anangularity which corresponds to that of the outer edges N5 of thegripping members and is adapted to engage these edges. When the pressuremember is screwed into the body 30, the gripping members are forcedinwardly. It will be noted that all sides of the gripping members extendbeyond the corresponding sides of the resilient body 20 so thatclearance spaces are provided to allow for the displacement of the body20 when the gripping members are forced inwardly.

In the modification illustrated in Fig. 6, an elongated lug 24A is showninstead of the bosses 24, 25. Openings of similar size and shape arewith this construction provided in the gripping members. The portions22A are symmetrically disposed in relation to the lug 24A.

ter is reversed as shown at IDA in Fig. 8 and the frustro-conicalinterior.

If desired the gripping members may be ce mented or otherwiseaffixedtothe body: I

Various modifications in construction, mode o operation, method and useof an invention may and do occur to others, especially after benefittingfrom knowledge of such a disclosure as that herein presented of theprinciples involved, but the invention itself is not confined to thepresent showing. t g

'Iclaim:

l. A circumferentially continuous machine tool collet to be actuated bya cam surface of a chuck,

said collet comprising a retainer in the form of a body of resilientmaterial having a central 1ongitudinalopening and having a plurality ofang'ularly spaced radially disposed slots extending from said opening tothe outer periphery of the body, said slots being open at one transverseedge and open at the other transverse edge throughout the major portionof the length of the body and portions of the body across one of thetrans- :verse edges of the slots intermediate the longitudinal ends ofthe body closing short parts of the slots, and alined bosses spaced fromsaid portions of the body, projecting from the sides of the slots, andrigid gripping members in the slots having tapered edges projecting fromthe body and arranged to be engaged by said cam surface,vnotches in theopposite edges of the gripping'members engaging the portions of thebodywhich are across the slots, said gripping members being providedwith orifices for receiving the lugs. 1

' 2'. A circumferentially continuous machine tool collet to be actuatedby a cam surface of a chuck, said collet comprising a retainer in theformer a tudinal opening and having a plurality of angularly spacedradially disposed slots extending from said opening-to theouterperiphery of the body, said slots being'open to said periphery and openat their inner edges throughout the major portion of the length of thebody and portions of the body across the inner edges of theslotsintermediate the longitudinal ends of the body closing body 20Amade with a cylindrical exterior and a vcollet to be actuated by a camsurface of a chuck,

said collet comprising a retainer in the form of a body ofresilientmaterialhaving a'central longitudinal opening and having aplurality of angu- 'lar1y spaced radially disposed slots extendin bodyof resilient material having a central longifrom said opening to theouter periphery of the body, said slots being open to said periphery andopen at their inner edges throughout the major portion of the length ofthe body and portions of the bodyacross the inner edges of the slotsintermediate the longitudinal ends of the body closing short parts ofthe slots, and alined bosses longitudinally spaced and laterally offsetfrom said portions of the body, projecting from the sides of the slots,and rigid gripping members in the slots having tapered outer edgesprojecting from the body and arranged to be engaged by said cam surface,notches in the inner edges of thegripping members engaging the portionsof the body which are across the slots, said gripping membersbeingprovided with orifices for receiving the lugs.

4. A circumferentially continuous machine tool collet to be actuatedby acam surface of a chuck, said collet comprising a retainer in the form ofa body of resilient material having a central longitudinal opening andhaving a plurality of angularly spaced radially disposed slots extendingfrom said opening to the outer periphery of the body,

said slots being open to said periphery and open at their inner edgesthroughout the major portion of the length of the body andlongitudinally spaced portions of the body across the inner edges of theslots intermediate the longitudinal ends of the body closing short partsof the slots, and alined bosses longitudinallyv spaced and laterallyofiset from said portions of the body, projecting from the sides of theslots, and rigid gripping members in the slots having tapered outeredges projecting from the body and arranged to be engaged by said camsurface, longitudinally spaced notches in the inner edges of the grippinmembers engaging the portions of the body which are across the slots,each of said gripping members being provided with an orifice forreceiving the lugs.-

ARTHUR'MERRICK STONER.

